From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753438Ab0CZLNb (ORCPT ); Fri, 26 Mar 2010 07:13:31 -0400 Received: from mx1.redhat.com ([209.132.183.28]:14763 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753186Ab0CZLNa (ORCPT ); Fri, 26 Mar 2010 07:13:30 -0400 Date: Fri, 26 Mar 2010 12:11:31 +0100 From: Oleg Nesterov To: Grzegorz Nosek Cc: Matt Helsley , Roland McGrath , Sukadev Bhattiprolu , containers@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: Testing lxc 0.6.5 in Fedora 13 Message-ID: <20100326111131.GA8604@redhat.com> References: <20100321195044.GA23757@megiteam.pl> <20100323212834.GH20796@count0.beaverton.ibm.com> <20100325213356.GB20541@megiteam.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100325213356.GB20541@megiteam.pl> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/25, Grzegorz Nosek wrote: > > On wto, mar 23, 2010 at 02:28:34 -0700, Matt Helsley wrote: > > On Sun, Mar 21, 2010 at 08:50:44PM +0100, Grzegorz Nosek wrote: > > > > > > > > > 2. Weird strace behaviour across pidns boundary > > > > > > When strace'ing (with -ff) lxc-start, I get a proper strace for the > > > directly spawned process and the container init. However, any processes > > > spawned by the container's init are not straced properly Yes, this is broken. More precisely, this wasn't even supposed to work. Even stracing of the sub-init itself (or global init btw) has problems, the straced init is not protected from unwanted signals. > > I'm suprised strace of ls works across pid namespaces. I've been looking > > at strace and it seemed to me that one kernel change and a bunch of strace > > changes are needed to make strace'ing in child pid namespaces work. Yes. First of all, tracehook_report_clone_complete() reports the wrong pid nr, as it seen inside the init's namespace. This is easy to fix, but I doubt this can help. IIRC strace doesn't use PTRACE_GETEVENTMSG at all, it looks at eax after syscall. > Eric > > Biederman's setns() patches also might help. > > Thanks for the patch and the detailed explanation. which patch? Oleg.